Acoustic Doppler current profiler （ADCP） uses acoustic energy directed along narrow beams for current measurement. In conventional method, the quantity of sampling affects the precision of fast Fourier transform （...Acoustic Doppler current profiler （ADCP） uses acoustic energy directed along narrow beams for current measurement. In conventional method, the quantity of sampling affects the precision of fast Fourier transform （FFT） algorithm, and the algorithm needs a large amount of data to process. A novel frequency estimator,enhanced least mean square （ELMS） algorithm for a single complex sinusoid in complex white Gaussian noise, is proposed in ADCP system. As sampling frequency equals 120 krad/s and the sampling number equals 240, the minimum resolving is 0.5 krad/s. All variances keep 11.1100. ELMS algorithm needs less data than FFT. And the robust algorithm can estimate the spectrum true value to 99.900 when the signal to noise ratio （SNR） is equal to 0 dB. Experiments prove that the estimation values will diverge much from the ideal when SNR is less than -6 dB.展开更多
在水声通信系统中,大多数多普勒频移因子估计方法未能很好地处理相对运动速度较高时计算复杂度与估计精度之间的关系。针对该情况,提出基于快速傅里叶变换(FFT)测频和模糊度函数的联合估计方法。通过FFT对单频脉冲信号进行测频以确定多...在水声通信系统中,大多数多普勒频移因子估计方法未能很好地处理相对运动速度较高时计算复杂度与估计精度之间的关系。针对该情况,提出基于快速傅里叶变换(FFT)测频和模糊度函数的联合估计方法。通过FFT对单频脉冲信号进行测频以确定多普勒频移因子的初步估计范围,再使用模糊度函数法在该范围内进行搜索,得到精确的多普勒频移因子。仿真结果表明,当信噪比大于-20 d B时,该方法在相对运动速度为-60 m/s^60 m/s时能保持高于0.02%的估计精度,且与单独使用模糊度函数的估计方法相比,具有较低的计算复杂度。展开更多
基金Supported by"863"Foundation of China (No.863-818-06-03).
文摘Acoustic Doppler current profiler （ADCP） uses acoustic energy directed along narrow beams for current measurement. In conventional method, the quantity of sampling affects the precision of fast Fourier transform （FFT） algorithm, and the algorithm needs a large amount of data to process. A novel frequency estimator,enhanced least mean square （ELMS） algorithm for a single complex sinusoid in complex white Gaussian noise, is proposed in ADCP system. As sampling frequency equals 120 krad/s and the sampling number equals 240, the minimum resolving is 0.5 krad/s. All variances keep 11.1100. ELMS algorithm needs less data than FFT. And the robust algorithm can estimate the spectrum true value to 99.900 when the signal to noise ratio （SNR） is equal to 0 dB. Experiments prove that the estimation values will diverge much from the ideal when SNR is less than -6 dB.
文摘在水声通信系统中,大多数多普勒频移因子估计方法未能很好地处理相对运动速度较高时计算复杂度与估计精度之间的关系。针对该情况,提出基于快速傅里叶变换(FFT)测频和模糊度函数的联合估计方法。通过FFT对单频脉冲信号进行测频以确定多普勒频移因子的初步估计范围,再使用模糊度函数法在该范围内进行搜索,得到精确的多普勒频移因子。仿真结果表明,当信噪比大于-20 d B时,该方法在相对运动速度为-60 m/s^60 m/s时能保持高于0.02%的估计精度,且与单独使用模糊度函数的估计方法相比,具有较低的计算复杂度。
